The instant invention relates to electroplating and more particlarly to a method and apparatus for rinsing electroplating solutions from the surfaces of articles after the plating thereof.
Most of the heretofore-known electroplating solution systems have generally comprised a single plating tank and a series of "drag-out" or rinse tanks which are positioned adjacent the plating tank for receiving and rinsing articles in a predetermined rinse sequence after they have been plated. For use and operation of a system of this type, an article is immersed in a plating solution in the plating tank and electrically connected to one terminal of a DC power source, and the other terminal of the DC power source is electrically conected to an electrode which is also immersed in the plating solution. When the DC power source is energized, the article is electroplated in a conventional manner, and the extent of the plating is determined by process parameters, such as the current density which is applied by the DC power source, the concentration of the plating solution, and the duration of the plating process. Finally, after an article has been plated to the desired extent in this manner, it is removed from the plating tank and then sequentially immersed in the "drag-out" tanks in order to rinse any plating solution which is carried on the surfaces of the article.
It is obvious that as a result of solution carryover, if a system of the above type is operated without frequently changing the rinse solutions in the various rinse tanks, the concentration levels of electroplating solution in the rinse solutions will rapidly reach intolerable levels. Because environmental regulations prohibit the discharge of liquids containing high quantities of metallic electroplating solutions into sewage systems, and also because electroplating solutions are relatively expensive, it is not practical to discard the rinse solutions used in an electroplating solution system when the concentration levels of electroplating solution in these rinse solutions become too high. Accordingly, it has generally been the practice to transfer rinse solutions from tank to tank in a system in the reverse order of the sequence of the plating and rinse tanks so that the plating solution in the plating tank is replenished with rinse solution from the first rinse tank (plus some plating chemicals), the rinse solution in the first rinse tank is replenished with rinse solution from the second rinse tank and so on, the solution in the last rinse tank being replenished with water. The operation of a plating solution system in this manner assures that substantially all of the plating solution which is carried over into the various rinse tanks is recovered, and also the concentrations of the plating solution in the various rinse tanks are maintained at equilibrium levels which gradually decrease with each sequential rinse tank. Obviously, in order to effectively operate a system of this type, it is important that an electroplated article is rinsed in the various rinse tanks in the prescribed sequence in order to effectively rinse all of the plating solution from the surfaces of the article and also in order to assure that the concentrations of the plating solution in the various rinse tanks are maintained at equilibrium levels. However, while plating solution systems of this type have been found to be generally effective, they have normally required several rinse tanks in order to assure effective removal of all of the electroplating solution from the surfaces of articles; and hence solution systems of this type have been relatively expensive, and they have normally required large areas of floor space. Further, if the various tanks of a system of this type are not positioned directly adjacent one another in the proper sequence, substantial quantities of plating and/or one or more of the rinse solutions are normally dripped or spilled onto the floor as articles are transferred from tank to tank.
The instant invention provides a novel method and apparatus for rinsing electroplating solution from the surfaces of articles after the articles have been plated, and the method and apparatus of the instant invention effectively overcome many of the problems associated with the hertofore known electroplating methods and solution systems. The apparatus of the instant invention is operative for receiving articles for rinsing electroplating solution therefrom and comprises a splash wall having an outwardly facing surface thereon, means for supporting at least one plated article in front of the outwardly facing surface, and an upwardly facing trough which is positioned beneath the outwardly facing surface and the article support means for receiving rinse solution and electroplating solution intermixed therewith which gravitates downwardly after the rinse solution has been sprayed onto the article. In the preferred embodiment of the apparatus, the trough is integrally attached to the lower end of the splash wall and means is provided for suspending the splash wall, the article support means, and the trough from a wall of an electroplating tank so that the splash wall is disposed adjacent the outer surface of the tank wall. For use of the apparatus in accordance with the method of the instant invention, an article which has been electroplated is positioned on the article support means in front of the splash wall, rinse solution is sprayed onto the article to remove electroplating solution from the surfaces thereof, and the rinse solution and any plating solution intermixed therewith which gravitates downwardly from the article and the wall is collected in the trough and transferred into the plating tank. Accordingly, the article is effectively and completely rinsed with a minimal amount of rinse solution, and substantially all of the electroplating solution which is removed from the plating tank as a result of carryover is recovered and returned to the plating tank. Further, while preferably the method is carried out utilizing the apparatus of the instant invention, other forms of the method which are carried out with other types of apparatus are also contemplated. In this connection broadly, the method of the instant invention for rinsing electroplating solution from the surface of an article is defined by a series of steps comprising spraying the article with a rinse solution such as water to remove electroplating solution from the surfaces thereof, collecting the rinse solution and any electroplating solution intermixed therewith, and transferring the collected rinse solution with plating solution intermixed therewith to the plating tank. Hence it is seen that the preferred form of the method which is carried out with the apparatus of the invention and the more general form of the method of the instant invention provide a novel process whereby electroplating solution can be effectively rinsed from the surfaces of articles utilizing minimal quantities of rinse solution and whereby substantially all of the electroplating solution which is carried on the surfaces of articles when they are removed from an electroplating tank is recovered and returned to the electroplating tank.
Apparatus and methods which are exemplary of the closest prior art to the instant invention of which the applicant is aware are disclosed in the U.S. Patents to Ishisaka, U.S. Pat. No. 1,771,680; Robinson, U.S. Pat. No. 2,665,698; Dolan et al, U.S. Pat. No. 3,276,983; Latawiec et al; U.S. Pat. No. 3,287,238 and Koering, U.S. Pat. No. 4,192,331. The apparatus and methods disclosed in these references relate generally to the types of apparatus and methods which have been used for electroplating articles for many years. However, they fail to suggest an apparatus for receiving an article for rinsing electroplating solution therefrom by spraying a rinse solution onto the article as per the apparatus of the instant invention. They also fail to disclose a method for rinsing electroplating solution from the surfaces of an article by spraying a rinse solution onto the article; and accordingly, for these reasons all of the above references are believed to be of only general interest.
Accordingly, it is a primary object of the instant invention to provide an effective apparatus for receiving an article for spraying a rinse solution thereon after the article has been electroplated so that electroplating solution is rinsed from the surfaces of the article.
Another object of the instant invention is to provide an effective method for rinsing electroplating solution from the surfaces of an article after it has been electroplated.
A still further object of the instant invention is to provide an effective apparatus for rinsing electroplating solution from the surfaces of an article, wherein substantially all of the electroplating solution is recovered and returned to an electroplating tank.
An even further object of the instant invention is to provide an effective apparatus for rinsing electroplating solution from the surfaces of an article, wherein the overall cost of the apparatus is minimized and wherein the apparatus occupies a minimal amount of floor space.